michael s
(Michael S)
#1
46 How should I treat atrial septal defects in
adults?
Seamus Cullen
A significant secundum atrial septal defect (ASD) will result in
volume and pressure overload of the right heart and may be
associated with reduced exercise tolerance, shortness of breath
and palpitations from atrial arrhythmias especially atrial fibril-
lation/flutter. Pulmonary vascular disease is a late complication,
rarely seen before the fourth or fifth decade. The clinical
suspicion of an ASD is confirmed by transoesophageal echo-
cardiography as transthoracic images are usually inadequate. The
presence of tricuspid regurgitation permits accurate assessment
of right heart pressures, otherwise right heart catheterisation is
required. Coronary angiography is indicated in patients over 40
years of age.
Indications for closure include symptoms (exercise intolerance,
arrhythmias), right heart volume overload on echocardiography,
the presence of a significant shunt (>2:1) or cryptogenic cerebro-
vascular events, especially associated with aneurysm of the oval
foramen and right to left shunting demonstrated on contrast
echocardiography during a Valsalva manoeuvre. Preoperative
arrhythmias may persist after closure of the ASD but are asso-
ciated with fewer symptoms. Reduction in left ventricular
compliance due to e.g. hypertension/myocardial infarction will
increase the left to right shunt through an ASD.
Closure of an ASD requires either surgery or transcatheter
intervention. The results of surgery are excellent with little or no
operative mortality in the absence of risk factors, e.g. pulmonary
hypertension, co-morbidity. However, it requires a surgical scar,
cardiopulmonary bypass and hospital stay of approximately 3–5
days. There is a small but definite risk of pericardial effusion with
the potential for cardiac tamponade following closure of an atrial
septal defect. The aetiology is poorly understood.
Transcatheter occlusion of ASDs is now established practice.
Several occlusion devices are available. Their efficacy and ease of
deployment have been demonstrated although long term data are
lacking. It is possible to close ASDs with a stretched diameter of up
to 34mm in size, providing there is a sufficient rim of atrial tissue.
Our policy is to perform a transoesophageal echocardiogram under
